- Directed Hydroxylation of sp2 and sp3 C-H Bonds Using Stoichiometric Amounts of Cu and H2O2
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The use of copper for C-H bond functionalization, compared to other metals, is relatively unexplored. Herein, we report a synthetic protocol for the regioselective hydroxylation of sp2 and sp3 C-H bonds using a directing group, stoichiometric amounts of Cu and H2O2. A wide array of aromatic ketones and aldehydes are oxidized in the carbonyl γ-position with remarkable yields. We also expanded this methodology to hydroxylate the β-position of alkylic ketones. Spectroscopic characterization, kinetics, and density functional theory calculations point toward the involvement of a mononuclear LCuII(OOH) species, which oxidizes the aromatic sp2 C-H bonds via a concerted heterolytic O-O bond cleavage with concomitant electrophilic attack on the arene system.
- Trammell, Rachel,D'Amore, Lorenzo,Cordova, Alexandra,Polunin, Pavel,Xie, Nan,Siegler, Maxime A.,Belanzoni, Paola,Swart, Marcel,Garcia-Bosch, Isaac
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p. 7584 - 7592
(2019/06/11)
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- Iridium- and rhodium-catalyzed C-H activation and formyl arylation of benzaldehydes under chelation-assistance
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Mild and efficient synthesis of benzophenones via Ir(iii)- and Rh(iii)-catalyzed, directing group-assisted formyl C-H arylation of benzaldehydes has been achieved using diaryliodonium salts, in which Rh(iii) and Ir(iii) catalysts exhibited a complementary
- Yang, Xifa,Wang, He,Zhou, Xukai,Li, Xingwei
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supporting information
p. 5233 - 5237
(2016/07/06)
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- Palladium-catalyzed ortho-CH-bond oxygenation of aromatic ketones
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A palladium-catalyzed C(sp2)-H bond oxygenation reaction is described. This protocol represents the first example of a C-H bond cleavage/C-O bond formation sequence, by employing a ketone moiety as the directing group. With this new catalytic method, a variety of ortho-acylphenols can be easily accessed from arylketones.
- Choy, Pui Ying,Kwong, Fuk Yee
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supporting information
p. 270 - 273
(2013/03/13)
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- Enantioselective synthesis of cyclic sulfamidates via Pd-catalyzed hydrogenation
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Using Pd(CF3;CO2)2/(S,S)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
- Wang, You-Qing,Yu, Chang-Bin,Wang, Da-Wei,Wang, Xiao-Bing,Zhou, Yong-Gui
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supporting information; experimental part
p. 2071 - 2074
(2009/04/18)
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- Direct acylation of phenol and naphthol derivatives in a mixture of graphite and methanesulfonic acid
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Graphite in methanesulfonic acid is used to prepare o-hydroxyketones by direct acylation of phenol and naphthol derivatives with carboxylic acids. Georg Thieme Verlag Stuttgart.
- Sharghi, Hashem,Hosseini-Sarvari, Mona,Eskandari, Razieh
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p. 2047 - 2052
(2007/10/03)
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- Sandmeyer reactions. Part 5.1 Estimation of the rates of 1,5-aryl/aryl radical translocation and cyclisation during Pschorr fluorenone synthesis with a comparative analysis of reaction energetics
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During the Pschorr cyclisation of 2-aroylphenyl radicals, a rearrangement occurs reversibly by 1,5-hydrogen transfer to give 2-benzoylaryl radicals. Rate constants of (1.2 ± 0.2) × 106 s-1 at 293 K are estimated for both the forward and back reactions in the equilibrium between 2-(4-methylbenzoyl)phenyl and 2-benzoyl-5-methylphenyl radicals. Assuming an empirical estimate of 1.6 × 10-2 dm3 mol-1 s-1 for the hypothetical rate of abstraction of hydrogen from benzene by phenyl radicals, the radical translocation is calculated to occur with a statistically corrected effective molarity of 2.2 × 108 mol dm-3. By contrast, the competing cyclisation, though occurring at a rate of (8.0 ± 0.9) × 105 s-1, exhibits an effective molarity of only 5.3 mol dm-3. The causes of these differences are analysed in terms of reaction mechanism.
- Chandler, Stephen A.
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p. 214 - 228
(2007/10/03)
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- Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
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Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
- Sharghi, Hashem,Kaboudin, Babak
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p. 2678 - 2695
(2007/10/03)
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- Infrared study of polysubstitution effects in benzophenones and acetophenones: contribution of inter and intracycle interaction mechanisms
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The carbonyl stretching frequencies of substituted 2-Me, 2,6-diMe, 2-MeO benzophenones and 2-Me, 2-MeO acetophenones have been measured in diluted CCl4 solutions.Two interaction mechanisms are observed.In X, Y substituted benzophenones with X on the same cycle as the ortho group and Y on the other cycle, it is shown that for X=Y, the effect of Y is greater than that of X except for very strong electron-releasing substituents.In this last case, the observed enhancement is attributed to the joint effects of intercycle interactions excercised on X and Y and of intracycle interaction on X.These results are corroborated by the study of substituted acetophenones in which only the intracycle mechanism can play a role.
- Goethals, G.,Nadio, L.,Uzan, R.
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p. 199 - 204
(2007/10/02)
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